Almost all of the discoveries are in the Great Rift Valley in river basins or old river basins. The combination of the geologic upheaval and erosion from the w

Almost all of the discoveries are in the Great Rift Valley in river basins or old river basins. The combination of the geologic upheaval and erosion from the water have literally left fossils sticking out of the ground. Likewise, discoveries are found in quarries and mines. This is how the first hominid discovery was found, A. africanus in a South Africa. The discoveries also make it seem like they just found a hominid skull, but in actuality they find hundreds of fossils (animals mostly, a few hominids) and it takes years to sort and identify the fossils. It always amazes me that the expert can take a small bone fragment and determine hominid vs deer vs monkey. Even further, which type of hominid they found, even from something like a skull fragment.